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Abstract:

A tinnitus masking system for use by a person having tinnitus The system
comprises a sound delivery system having left and right ear-level audio
delivery devices and is configured to deliver a masking sound to the
person via the audio delivery devices such that the masking sound appears
to originate from a virtual sound source location that substantially
corresponds to the spatial location in 3D auditory space of the source of
the tinnitus as perceived by the person. The masking sound being
represented by left and right audio signals that are converted to audible
sound by the respective audio delivery devices.

Claims:

1. A tinnitus masking system for use by a person having tinnitus
comprising: a sound delivery system having left and right ear-level audio
delivery devices, the sound delivery system being configured to deliver a
masking sound to the person via the audio delivery devices such that the
masking sound appears to originate from a virtual sound source location
that substantially corresponds to the a spatial location in 3D auditory
space of a source of the tinnitus as perceived by the person, the masking
sound being represented by left and right audio signals that are
converted to audible sound by the respective audio delivery devices.

2. A tinnitus masking system according to claim 1 wherein the sound
delivery system further comprises an audio controller that is configured
to synchronise the delivery of the left and right audio signals to the
respective audio delivery devices.

3. A tinnitus masking system according to claim 2 wherein the audio
controller is integrated with one or both of the audio delivery devices.

4. A tinnitus masking system according to claim 2 wherein the audio
controller is external and in signal communication with the audio
delivery devices.

5. A tinnitus masking system according to claim 2 wherein the masking
sound is provided in the form of a digital audio file that is stored in
memory in the audio controller for playback over the audio delivery
devices.

6. A tinnitus masking system according to claim 2 wherein the audio
controller comprises a sound processor that is configured to generate the
left and right audio signals of the masking sound in real-time for
playback over the audio delivery devices.

7. A tinnitus masking system according to claim 1 wherein the sound
delivery system is configured to modulate the intensity of left and right
audio signals of the masking sound with a periodic ramping profile such
that the intensity of the masking sound at playback varies in accordance
with the periodic ramping profile

8. A tinnitus masking system according to claim 7 wherein the ramping
profile comprises a series of periodically repeating ramps, each ramp
being defined by an initial increase in intensity and ending in a
decrease in intensity, and wherein the rate of increase in intensity is
slower than the subsequent rate of decrease in intensity.

9. A tinnitus masking system according to claim 1 wherein the masking
sound is configured to have one or more sound attributes that correspond
to one or more of the sound attributes of the tinnitus as perceived by
the person.

10. A tinnitus masking system according to claim 9 wherein the sound
attributes comprise any one or more of the following: pitch, frequency,
bandwidth, temporal properties, intensity, loudness, and sound type.

11. A tinnitus masking system according to claim 1 wherein the audio
delivery devices are hearing aids.

12. A tinnitus masking system according to claim 1 wherein the audio
delivery devices are headphones or earphones.

13. A method of masking a person's tinnitus comprising: delivering a
masking sound to the person via left and right ear-level audio delivery
devices such that the masking sound appears to originate from a virtual
sound source location that substantially corresponds to a spatial
location in 3D auditory space of a source of the tinnitus as perceived by
the person.

14. (canceled)

15. A system for determining a spatial property of tinnitus as perceived
by a person comprising: a sound generation system that is operable to
present test sounds to the person from a series of virtual sound source
locations in 3D auditory space; and a feedback system that is arranged to
receive person feedback indicative of the virtual sound source location
that most closely corresponds to the spatial location in 3D auditory
space of the source of the tinnitus as perceived by the person and output
spatial information indicative of the spatial location of the source of
the tinnitus based on the person's feedback.

16. A system according to claim 15 wherein the sound generation system is
configured to sequentially present test sound to the person from a range
of different virtual sound source locations.

17. A system according to claim 15 wherein the sound generation system is
user operable to present the test sounds from user selected virtual sound
source locations.

18. A system according to claim 15 wherein the test sound has one or more
sound attributes that substantially correspond or match one or more of
the perceived sound attributes of the person's tinnitus.

19. A system according to claim 18 wherein the sound attributes comprise
any one or more of the following: pitch, frequency, bandwidth, temporal
properties, intensity, loudness, and sound type.

20. A system according to claim 15 wherein the sound generation system is
configured to present the test sound to the person sequentially at
different azimuth and elevation angles within respective predetermined
azimuth and elevation ranges relative to a reference point in a 3D
auditory space reference frame.

21. A system according to claim 20 wherein the reference point is the
center of the midline axis between the ears.

22. A system according to claim 20 wherein the sound generation system is
configured to present the test sounds by continuously sweeping through
the entire azimuth and elevation ranges.

23. A system according to claim 20 wherein the sound generation system is
configured to present the test sounds sequentially at a series of
discrete azimuth and elevation angles.

24. A method of determining a spatial property of tinnitus as perceived
by a person comprising the steps of: sequentially presenting test sounds
to the person from a series of virtual sound source locations in 3D
auditory space; and receiving feedback from the person as to virtual
sound source location that most closely corresponds to the spatial
location in 3D auditory space of the source of the tinnitus as perceived
by the person.

25. A spatial masking sound generation system for a person having
tinnitus comprising: a sound processor that is arranged to receive a
masking sound and spatial information indicative of the spatial location
in 3D auditory space of the source of the tinnitus as perceived by the
person, and which is further configured to modify the spatial playback
properties of the masking sound based on the spatial information so as to
generate a spatial masking sound for playback to the person via left and
right ear-level audio delivery devices such that the sound appears to
originate from a virtual sound source location that substantially
corresponds to the spatial location of the source of the tinnitus as
perceived by the person.

26. A method of generating a spatial masking sound for a person having
tinnitus comprising the steps of: receiving or generating a masking
sound; receiving or assessing spatial information indicative of the
spatial location in 3D auditory space of the source of the tinnitus as
perceived by the person; and modifying the spatial playback properties of
the masking sound based on the spatial information so as to generate a
spatial masking sound for playback to the person via left and right
ear-level audio delivery devices such that the sound appears to originate
from a virtual sound source location that substantially corresponds to
the spatial location of the tinnitus as perceived by the person.

27. A method of generating a personalised spatial masking sound for a
person having tinnitus comprising: according to claim 26, further
comprising: assessing one or more sound attributes of the tinnitus as
perceived by the person; and wherein the step of receiving or generating
a masking sound comprises receiving or generating a masking sound having
one or more sound attributes that substantially correspond to the
perceived sound attributes of the person's tinnitus.;

28. A method according to claim 27 wherein the step of assessing one or
more sound attributes of the tinnitus as perceived by the person
comprises operating an assessment system to generate test sounds having
configurable sound attributes for playback to the person, the assessment
system being controlled an operable graphical user interface.

29. A method according to claim 28 wherein the step of assessing one or
more sound attributes of the tinnitus as perceived by the person further
comprises receiving the person's feedback on the test sound that most
closely corresponds to their perceived tinnitus for each sound attribute
being assessed.

30. A method according to claim 26 further comprising assessing the
intensity of the tinnitus as perceived by the person at the location of
the tinnitus sound source in 3D auditory space and further modifying the
intensity of the masking sound based on the assessed intensity.

31. A method according to claim 27 wherein the step of assessing one or
more of the sound attributes of the tinnitus as perceived by the person
comprises assessing any one or more of the following attributes: pitch,
frequency, bandwidth, temporal properties, intensity, loudness, and sound
type.

32. A method according to claim 26 wherein the step of receiving or
assessing spatial information indicative of the spatial location in 3D
auditory space of the source of the tinnitus as perceived by the person
comprises presenting test sounds to the person from a range of virtual
sound source locations in 3D auditory space; and receiving feedback from
the person as to virtual sound source location that most closely
corresponds to the spatial location in 3D auditory space of the source of
the tinnitus as perceived by the person.

Description:

FIELD OF THE INVENTION

[0001] The present invention relates to the treatment of tinnitus. In
particular, although not exclusively, the present invention is a tinnitus
treatment system and method that may be employed by tinnitus sufferers to
provide short-term and/or long-term relief.

BACKGROUND TO THE INVENTION

[0002] Tinnitus is the perception of sound in the absence of a
corresponding external source. It can be perceived in one or both ears,
or in the head, or outside the head. It is usually described as a ringing
noise, but can also be in other forms such as hissing, buzzing, or
roaring sounds. Tinnitus can be intermittent or it can be continuous and
in such cases can be a cause of great distress to the sufferer.

[0003] Tinnitus is not a disease but a symptom resulting from a range of
possible underlying causes including, for example, ear infections,
foreign objects or wax in the ear, nose allergies, noise-related trauma,
side effect of medication or other unexplained causes. Currently, there
is no surgical cure for tinnitus. However, temporary relief for sufferers
can be provided by external sound devices, for example masking
instruments, as tinnitus sufferers often indicate that their tinnitus is
less audible in the presence of sounds.

[0004] Typically, masking instruments use a noise generator to deliver a
masking sound to the patient in order to mask the tinnitus. The masking
instruments are often customised in that the frequency and intensity of
the masking sound is often matched to the frequency and intensity of the
tinnitus as perceived by the individual patient, and which can be
assessed by an audiologist using various tests. Masking can be provided
through ear-level or non-ear level sound generation devices including,
for example, table top generators, bedside maskers, personal sound
systems, standalone ear-level "maskers" for patients with normal hearing,
and combination devices such as maskers integrated with hearing aids for
the hearing impaired.

[0005] Another approach to tinnitus management, is the recent trend toward
using Tinnitus Retraining Therapy (TRT). TRT is a specific clinical
method based on a neurophysiological model of tinnitus. The method is
aimed at habituation of reactions evoked by tinnitus, and subsequently
habituation of the tinnitus perception. Typically, the therapy involves
counseling, aimed at reclassification of tinnitus to a category of a
neutral signal, and sound therapy, aimed at weakening tinnitus-related
neuronal activity. Effectively the TRT method is trying to retrain the
patient's brain so that they treat their tinnitus similar to natural
sounds that they can accommodate.

[0006] It is an object of the present invention to provide an improved
tinnitus treatment system and method, or to at least provide the public
with a useful choice.

SUMMARY OF THE INVENTION

[0007] In a first aspect, the present invention broadly consists in a
method of masking a person's tinnitus comprising: delivering a masking
sound to the person via left and right ear-level audio delivery devices
such that the masking sound appears to originate from a virtual sound
source location that substantially corresponds to the spatial location in
3D auditory space of the source of the tinnitus as perceived by the
person

[0008] In a second aspect, the present invention broadly consists in a
tinnitus masking system for use by a person suffering from tinnitus
comprising: a sound delivery system having left and right ear-level audio
delivery devices, the sound delivery system being configured to deliver a
masking sound to the person via the audio delivery devices such that the
masking sound appears to originate from a virtual sound source location
that substantially corresponds to the spatial location in 3D auditory
space of the source of the tinnitus as perceived by the person, the
masking sound being represented by left and right audio signals that are
converted to audible sound by the respective audio delivery devices.

[0010] Preferably, the sound delivery system further comprises an audio
controller that is operable to control or trigger synchronized delivery
of the left and right audio signals to the respective audio delivery
devices.

[0011] Preferably, the masking sound is provided in the form of a digital
audio file that is stored in memory in the audio controller for playback.
Alternatively, the left and right audio signals of the masking sound are
generated in real-time by a sound processor of the audio controller.

[0012] In one form, the audio controller is partially or completely
integrated or onboard one or both of the audio delivery devices. In
another form, the audio controller may be a separate external device that
sends the left and right audio signals to the audio delivery devices via
a wired connection or wireless communication.

[0013] In a third aspect, the present invention broadly consists in a
method of determining a spatial property of tinnitus as perceived by a
person comprising the steps of: sequentially presenting test sounds to
the person from a series of virtual sound source locations in 3D auditory
space; and receiving feedback from the person as to virtual sound source
location that most closely corresponds to the spatial location in 3D
auditory space of the source of the tinnitus as perceived by the person.

[0014] In a fourth aspect, the present invention broadly consists in a
system for determining a spatial property of tinnitus as perceived by a
person comprising: a sound generation system that is operable to present
test sounds to the person from a series of virtual sound source locations
in 3D auditory space; and a feedback system that is arranged to receive
person feedback indicative of the virtual sound source location that most
closely corresponds to the spatial location in 3D auditory space of the
source of the tinnitus as perceived by the person and output spatial
information indicative of the spatial location of the source of the
tinnitus based on the person's feedback.

[0015] In one form, the sound generation system is configured to
sequentially present test sound to the person from a range of different
virtual sound source locations. In another form, the sound generation
system is user operable to present the test sounds from user selected
virtual sound source locations.

[0016] Preferably, the test sound has one or more sound attributes that
substantially correspond or match one or more of the perceived sound
attributes of the person's tinnitus. By way of example, the sound
attributes may comprise any one or more of the following: pitch,
frequency, bandwidth, temporal properties, intensity, loudness, or sound
type.

[0017] Preferably, the test sounds are presented sequentially at different
azimuth and elevation angles within respective predetermined azimuth and
elevation ranges relative to a referene point in a 3D auditory space
reference frame. Preferably, the reference point is the center of the
midline axis between the ears.

[0018] Preferably, the azimuth is the angle of a vector about the
reference point in a reference plane extending horizontally through the
center of the person's head, and the elevation is the angle of the vector
above or below the reference plane.

[0019] Preferably, the test sounds are continuously swept through the
entire azimuth and elevation ranges. Alternatively, the test sounds may
be sequentially presented at a series of discrete azimuth and elevation
angles.

[0020] In a fifth aspect, the present invention broadly consists in a
method of generating a spatial masking sound for a person having tinnitus
comprising the steps of: receiving a masking sound, receiving spatial
information indicative of the spatial location in 3D auditory space of
the source of the tinnitus as perceived by the person; modifying the
spatial playback properties of the masking sound based on the spatial
information so as to generate a spatial masking sound that may be played
to the person via left and right ear-level audio delivery devices such
that the sound appears to originate from a virtual sound source location
that substantially corresponds to the spatial location of the tinnitus as
perceived by the person.

[0021] In a sixth aspect, the present invention broadly consists in a
spatial masking sound generation system for a person having tinnitus
comprising: a sound processor that is arranged to receive a masking sound
and spatial information indicative of the spatial location in 3D auditory
space of the source of the tinnitus as perceived by the person, and which
is further configured to modify the spatial playback properties of the
masking sound based on the spatial information so as to generate a
spatial masking sound that may be played to a person via left and right
ear-level audio delivery devices such that the sound appears to originate
from a virtual sound source location that substantially corresponds to
the spatial location of the source of the tinnitus as perceived by the
person.

[0022] Preferably, the spatial masking sound is represented by left and
right audio signals. More preferably, the spatial masking sound is stored
or compiled into a digital audio file in any suitable audio format or
other sound recording format, whether digital or analogue.

[0023] Preferably, the audio delivery devices are headphones, earphones,
hearing aids, or any other suitable audio transducers for converting the
audio signals into audible sound.

[0024] Preferably, the masking sound has sound attributes that are
configured to substantially correspond to one or more of the sound
attributes of the tinnitus as perceived by the person. By way of example,
the sound attributes may comprise any one or more of the following:
pitch, frequency, bandwidth, temporal properties, intensity, loudness, or
sound type.

[0025] In a seventh aspect, the present invention broadly consists in a
tinnitus masking audio system for a person having tinnitus comprising:
left and right ear-level audio delivery devices that convert respective
left and right audio input signals into audible sound, the left and right
audio input signals representing a masking sound having a virtual sound
source location in 3D auditory space that substantially corresponds to
the spatial location of the source of the tinnitus as perceived by the
person; and an audio controller that is operable to coordinate
synchronized playback of the left and right audio signals over their
respective audio delivery devices.

[0027] Preferably, the masking sound is provided in the form of a digital
audio file that is stored in memory in the audio controller for playback.
Alternatively, the left and right audio signals of the masking sound are
generated in real-time by a sound processor of the audio controller.

[0028] In one form, the audio controller is partially or completely
integrated or onboard one or both of the audio delivery devices. In
another form, the audio controller may be a separate external device that
sends the left and right audio signals to the audio delivery devices via
a wired connection or wireless communication.

[0029] In an eighth aspect, the present invention broadly consists in a
method of generating a personalised spatial masking sound for a person
having tinnitus comprising: [0030] assessing one or more sound
attributes of the tinnitus as perceived by the person; [0031] generating
a masking sound having one or more sound attributes that substantially
correspond to the perceived sound attributes of the person's tinnitus;
[0032] assessing the location of the tinnitus sound source in 3D auditory
space as perceived by the person; and [0033] modifying the spatial
properties of the masking sound based on the assessed tinnitus sound
source location so as to generate a spatial masking sound that may be
played to the person via left and right ear-level audio delivery devices
such that the sound appears to originate from a virtual sound source
location that substantially corresponds to the spatial location of the
source of the tinnitus as perceived by the person.

[0034] Preferably, the step of assessing one or more sound attributes of
the tinnitus as perceived by the person comprises operating an assessment
system to generate test sounds having configurable sound attributes for
playback to the person, the assessment system being controlled by an
operable graphical user interface. More preferably, this step further
comprises receiving the person's feedback on the test sound that most
closely corresponds to their perceived tinnitus for each sound attribute
being assessed.

[0035] Additionally, or alternatively, the step of assessing one or more
sound attributes of the tinnitus as perceived by the person comprises
testing any one or more of the following: pitch-matching,
loudness-matching, tinnitus specific measures, minimum masking level,
residual inhibition, loudness growth and discomfort.

[0036] Preferably, the method further comprises the step of assessing the
intensity of the tinnitus as perceived by the person at the location of
the tinnitus sound source in 3D auditory space and further modifying the
intensity of the masking sound based on the assessed intensity.

[0037] By way of example, the sound attributes may comprise any one or
more of the following: pitch, frequency, bandwidth, temporal properties,
intensity, loudness, or sound type.

[0038] Preferably, assessing the location of the tinnitus sound source in
3D auditory space as perceived by the person comprises sequentially
presenting test sounds to the person from a range of virtual sound source
locations in 3D auditory space; receiving feedback from the person as to
virtual sound source location that most closely corresponds to the
spatial location in 3D auditory space of the source of the tinnitus as
perceived by the person. More preferably, the test sound is the masking
sound.

[0039] Preferably, modifying the spatial properties of the masking sound
comprises employing sound localization processing techniques and
algorithms based any one or more of the following: ITD, ILD, and HRTFs.

[0040] The phrase "ear-level audio delivery device" as used in this
specification and claims is intended to cover any type of audio delivery
device that can be worn or located on, over or in a person's ear, whether
a standalone audio component or integrated with another electronic device
or system, and which can be driven to produce audible sound, including,
by way of example only and not limited to, headphones, ear buds, and
hearing aids.

[0041] The phrase "3D auditory space" as used in the specification and
claims is intended to mean, unless the context suggests otherwise, the
volume of space, whether external to a person or internal, from which
actual or perceived sounds are determined as originating from according
to the sound localisation processing of the person's brain.

[0042] The phrase "masking sound" as used in the specification and claims
is intended to mean, unless the context suggests otherwise, any type of
sound that can be used to mask (wholly or partially), cover or
desensitize tinnitus as perceived by a person with the objective of
relieving and/or desensitizing the person from the tinnitus sound over
time and including for example, but not limited to, music, sound effects,
background noise, white or broadband ,noise, or any combination of such
sounds or other sounds suitable for this purpose.

[0043] The term "comprising" as used in this specification and claims
means "consisting at least in part of". When interpreting each statement
in this specification and claims that includes the term "comprising",
features other than that or those prefaced by the term may also be
present. Related terms such as "comprise" and "comprises" are to be
interpreted in the same manner.

[0044] As used herein the term "and/or" means "and" or "or", or both.

[0045] As used herein "(s)" following a noun means the plural and/or
singular forms of the noun.

[0046] The invention consists in the foregoing and also envisages
constructions of which the following gives examples only.

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Preferred embodiments of the invention will be described by way of
example only and with reference to the drawings, in which:

[0048] FIG. 1 is a flow diagram showing an overview of the steps in a
method for generating a spatial masking sound for a patient suffering
tinnitus in accordance with an embodiment of the invention;

[0049] FIG. 2 is a flow diagram showing a more detailed breakdown of the
steps in FIG. 1 in accordance with an embodiment of the invention;

[0050]FIG. 3 shows a screen shot of the graphical user interface of an
audiometer assessment interface of a tinnitus diagnosis system for use in
calibration in accordance with an embodiment of the invention;

[0051]FIG. 4 shows a screen shot of the graphical user interface of a
tone/bandnoise pitch match function interface of the tinnitus diagnosis
system in accordance with an embodiment of the invention;

[0052]FIG. 5 shows a screen shot of the graphical user interface of a
volume function interface of the tinnitus diagnosis system in accordance
with an embodiment of the invention;

[0053]FIG. 6 shows a screen shot of the graphical user interface of a
first tinnitus sound-match function interface of the tinnitus diagnosis
system in accordance with an embodiment of the invention;

[0054]FIG. 7 shows a screen shot of the graphical user interface of a
find sound search feature of a second tinnitus sound-match function
interface of the tinnitus diagnosis system in, accordance with an
embodiment of the invention;

[0055]FIG. 8 shows a screen shot of the graphical user interface of a
format sound search feature of the second tinnitus sound-match function
interface of the tinnitus diagnosis system in accordance with an
embodiment of the invention;

[0056]FIG. 9 shows a screen shot of the graphical user interface of a
sound player feature of the second tinnitus sound-match function
interface of the tinnitus diagnosis system in accordance with an
embodiment of the invention;

[0057] FIG. 10A is a schematic representation of the angular data used to
characterise the spatial characteristics of the tinnitus sound source as
perceived by the patient;

[0058] FIG. 10B is a midline cross-sectional top plan view of a patient's
head and showing the X and Y axes of a 3D auditory space reference frame;

[0059] FIG. 10C is a midline cross-sectional elevation view of the
patient's head of FIG. 10B and shows the X and Z axes of the 3D auditory
space reference frame;

[0060]FIG. 11 shows a screen shot of the graphical user interface of a 3D
spatial location function interface of the tinnitus diagnosis system in
accordance with an embodiment of the invention;

[0061]FIG. 12 shows a screen shot of the graphical user interface of a
tinnitus intensity function interface of the tinnitus diagnosis system in
accordance with an embodiment of the invention;

[0062]FIG. 13A shows a diagram of a configurable ramping architecture for
modulating the intensity of the spatial masking sound in accordance with
an embodiment of the invention;

[0063]FIG. 13B shows an example of a saw-tooth ramping profile for
modulating the intensity of the spatial masking sound in accordance with
an embodiment of the invention;

[0064]FIG. 14 is a schematic block diagram of a sound processor system
for generating a spatial masking sound using virtual acoustic space
techniques in accordance with an embodiment of the invention;

[0065] FIG. 15a is a schematic block diagram showing the main modules of a
tinnitus treatment system having a first form of hearing aid, having a
stored spatial masking signal, that is controlled by a remote control in
accordance with an embodiment of the invention;

[0066] FIG. 15b is a schematic block diagram showing the main modules of a
tinnitus treatment system having a second form of hearing aid that
generates a spatial masking signal and that is controlled by a remote
control in accordance with an embodiment of the invention;

[0067]FIG. 16 is a schematic diagram showing the hardware devices of a
tinnitus treatment system employing synchronised left and right hearing
aids controlled by a remote control in accordance with FIGS. 15A and 15B;

[0068]FIG. 17 is a schematic block diagram showing the main modules of a
tinnitus treatment system having a hearing aid that is controlled by an
external audio control device that is configured to generate the spatial
masking signal for the hearing aid;

[0069]FIG. 18 is a schematic diagram showing examples of various hardware
devices that can be employed to implement the tinnitus treatment system
shown in FIG. 17, and in particular employing synchronised left and right
hearing aids that can be driven by a range of different audio control
devices;

[0070] FIG. 19 is a schematic diagram showing the hardware devices that
can be employed to implement the tinnitus treatment system shown in FIG.
17, and in particular employing left and right hearing aids that are
synchronously driven by an external audio control device; and

[0071]FIG. 20 shows a schematic diagram of hardware implementation of
tinnitus treatment system of another embodiment of the invention that
employs left and right stereo headphones that may be driven by various
audio control devices.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

1. Overview of Tinnitus Treatment Method and System

[0072] The invention relates to a tinnitus treatment system and method
that is based on masking the tinnitus and/or desensitising the patient to
the tinnitus. It has been identified that some of the distress associated
with tinnitus is related to a violation of tinnitus perception from
normal Auditory Scene Analysis (ASA). In particular, it has been
identified that neural activity forming tinnitus is sufficiently
different from normal sound activity that when formed into a whole image
it conflicts with memory of true sounds. In other words. tinnitus does
not localise to an external source. An inability to localise a sound
source is "unnatural" and a violation of the fundamental perceptual
process. Additionally, it has been identified that it is a lack of a
context, or a lack of behaviourally relevant meaning, that force the
brain too repeatedly or strongly attend to the tinnitus signal. For
example, the sound of rain in the background is easily habituated to. The
sound is associated with a visual and tactile perception or perceptual
memory of rain as well. The context of the sound is understood so it can
be processed and dismissed as unworthy of further attention. However,
there is no such understanding of the tinnitus signal, which does not
correspond to a true auditory object.

[0073] In some embodiments, the tinnitus treatment and system employs
customised informational masking and desensitisation. Informational
masking acts at a level of cognition and limits the brains capacity to
process tinnitus, rather than "drowning it out", which is what some
traditional white noise (energetic) maskers attempt.

[0074] The tinnitus treatment system and method presents a masking sound
to the patient from a virtual sound source location in 3D auditory space
that substantially corresponds to the spatial location of the source of
the tinnitus as perceived by the patient. In some embodiments, the
spatial 3D masking sound may also comprise other informational masking
features, such as spectral, temporal, and/or intensity sound attributes
that are matched to substantially correspond to the tinnitus sound as
perceived by the patient. The system and method aims to enhance tinnitus
masking by spatially overlapping the perceived tinnitus location and the
spatial representation (or the virtual sound source location) of the
masking sound.

[0075] As will be described in further detail later, the tinnitus
treatment system and method employs virtual acoustic technology, such as
a Virtual Acoustic Space (VAS) techniques or virtual surround sound
processing, to present or deliver the masking sound to the patient so as
to be perceived to originate or emanate from a predetermined direction
and/or location in 3D auditory space, whether in the patient's head or
external to the patient's head. Typically, the virtual acoustic
technology can deliver a spatial masking sound via a pair of stereo (left
and right) audio delivery devices such as, but not limited to, ear-level
devices such as headphones, earplugs or hearing aids that are worn by the
patient.

[0076] Referring to FIG. 1, an overview of an embodiment of the tinnitus
treatment method 10 is shown. A preferred order of steps is shown by way
of example only, but it will be appreciated that the order may be altered
or varied in alternative forms of the treatment method. Additionally,
some steps or stages may be omitted in other forms of the treatment
method.

[0077] The first step 12 involves diagnosing the patient's tinnitus
characteristics, as the spatial masking sound is customised for each
patient. In this embodiment, the tinnitus diagnosis step 12 comprises
five main stages. Firstly, a sound behavioural calibration diagnosis 62
is conducted to determine the patient's individual absolute hearing
thresholds (audiogram) and uncomfortable loudness levels. Secondly,
tinnitus sound attributes 14 are assessed. The tinnitus sound attributes
assessed for the patient may comprise any one or more of the following:
perceived sound characteristics (e,g, sound type, such as but not limited
to pure tone, noise, environmental sounds, or any other sounds),
bandwidth, temporal properties, loudness (intensity), and pitch. Such
sound attributes or features can be assessed by an audiologist or
clinician using various audio tests as will be explained in detail later.
While not essential, it is desirable to assess the patient's perceived
sound attributes of their tinnitus as in some embodiments the masking
sound may be configured to match one or more of the sound attributes of
the perceived tinnitus. For example, in the third stage, a tinnitus
synthetic sound 15 matching one or more of the assessed sound attributes
may be generated for use in the next assessment stages. This will not
necessarily always be the case as in some embodiments unmodified masking
sounds may be delivered to the patient, with the only characteristics
overlapping being the spatial characteristics as explained next.

[0078] The fourth stage of the tinnitus diagnosis stage 12 involves
assessing the spatial location 16 in 3D auditory space of the sound
source location of the tinnitus as perceived by the patient. By way of
example, the patient may perceive the tinnitus sound as originating from
one ear, both ears, within their head or external to their head. Tests
can be carried out by audiologist or clinician to determine the sound
source location of the tinnitus as perceived by the patient, as will be
explained in more detail later. The spatial location of the perceived
tinnitus source may be represented in various forms in 3D auditory space,
but in this embodiment the spatial location of the tinnitus is
represented by a 3D direction vector that represents the direction from
which the patient perceives their tinnitus as originating from relative
to a reference point, such as the centre of their head or any other
desired reference. In alternative forms, the 3D spatial location
information may comprise both a 3D direction vector in 3D auditory space
along with associated magnitude information representing the distance
between the perceived tinnitus sound source location and the reference
point. In some cases a predetermined distance to the perceived tinnitus
source from the reference point (e.g. center of patient's head) will be
assumed for the patient. This predetermined distance may be based on the
sound localisation techniques or algorithms used.

[0079] The fifth stage of the tinnitus diagnosis stage 12 involves
assessing the tinnitus intensity 17 in the spatial location in 3D
auditory space. Tests can be carried out by audiologist or clinician to
determine the intensity of the tinnitus as perceived by the patient as
will be explained in detail later.

[0080] The tinnitus sound attribute information, spatial information, and
tinnitus intensity information determined during the tinnitus diagnosis
stage 12 is used as input for the following masking sound parameter
setting steps 18 and 20. Firstly, a masking sound is selected and its
sound parameters personalised 18 in view of the patient's tinnitus
diagnosis results. The masking sound selected may, for example, be any
sound recording or noise, such as music, white noise, environmental
sounds, natural sounds, sound effects, or the like. One or more of the
sound attributes for the masking sound may be configured to match the
corresponding parameters of the tinnitus sound as perceived by the
patient in the diagnosis step 14. Alternatively, the masking sound
selected may be the synthetic sound generated at 15 in the tinnitus
diagnosis step 14.

[0081] Various optional sound processing parameters 20 may then be
configured, such as the masking sound play time, sound diffuse-field, and
any desired playback intensity variation, such as ramping.

[0082] Once the desired masking sound parameters are set, the selected
masking sound is signal processed at step 22 using virtual acoustic
technology to generate a spatial masking sound that appears to originate
in 3D auditory space from the same spatial location as the patient's
perceived tinnitus source location. Additionally, sound processing may be
employed to modify one or more of the masking sound attributes to match
corresponding tinnitus sound attributes, depending on the desired
personalisation settings from step 18.

[0083] The spatial masking sound output from step 22 may be in any
suitable form for storage and playback, including any analogue storage
medium or a digital sound file. In some embodiments, the spatial masking
sound will be represented by a stereo audio signal and may be provided in
various audio formats, whether analogue or digital, and including for
example wav or mp3 file formats. It will also be appreciated that the
spatial masking sound may be stored on any suitable medium, whether
analogue or digital, including on magnetic tapes, optical storage mediums
such as CDs or DVDs, or readable memory devices, such as hard drives,
memory sticks, whether standalone or part of another media, communication
or entertainment device. As will be explained in more detail later, in
preferred embodiments the spatial masking sound generation method is
primarily employed for generating a masking sound for playback over
hearing aids or headphones worn by the patient. In the context of hearing
aids, these may have an onboard sound storage and/or generation system or
may communicate with an external sound storage and/or generation system
or device. In embodiments in which the sound generation system is onboard
the audio delivery devices (e.g. hearing aids) or audio controller, the
spatial masking sound output format may be configured to suit the audio
delivery device input signal requirements.

[0084] The final step 24 in the treatment method is the playback of the
spatial masking sound to the patient via a sound delivery system. The
sound delivery system may be operated to play the spatial masking sound
to the patient in accordance with a treatment plan. For example, the
patient may be instructed to play the spatial masking sound at particular
times during the day or when the tinnitus is most distressing and there
may be customised treatment plans developed for each patient depending on
their requirements and tinnitus distress profile.

[0085] In some embodiments, the spatial masking sound is provided in the
form of a stereo audio signal that can be delivered or presented to the
patient via left and right audio delivery devices, such as headphones or
hearing aids at the ear level.

[0086] The stereo audio signal may be delivered to the audio delivery
devices via any suitable type of audio control device having sound
processing and playback capabilities, including for example a personal
computer, PDA, cell phone, or portable audio player (e.g. iPod or mp3
player). Alternatively, the audio delivery devices and audio control
device that stores and controls playback of the spatial masking system
may be a standalone integrated treatment device or the audio control
device may be integrated into hearing aids or the like.

2. An Example Embodiment of the Tinnitus Treatment Method and System

[0087] Referring to FIG. 2, an example embodiment of the tinnitus
treatment method will be explained in more detail with reference to the
overview previously provided.

Assessment Tools for Tinnitus Diagnosis

[0088] The following tinnitus diagnosis 12 assessments in the treatment
method may be performed using conventional audiology assessment
techniques and systems for generating a profile of the sound attributes
of an individual's tinnitus and conventional methods of storing or
recording such information, whether electronically or otherwise.
Additionally or alternatively, one or more of the tinnitus diagnosis
assessments may be performed using a customised electronic tinnitus
diagnosis system in the form of software running on a host computer
system, which may be a Personal Computer having a processor, memory, data
storage, user interface, display, and audio output interface for driving
speakers, headphones, hearing aids or other connectable audio delivery
devices for delivering test sounds generated by the assessment interfaces
to the patient being assessed.

[0089] As will be explained further by way of example below, the tinnitus
diagnosis system software may comprise one or more assessment interfaces
or functions to assist the audiologist or clinician in profiling a
patient's subjective tinnitus experience in terms of information relating
to any of the sound attributes 14, 3D spatial location 16, and tinnitus
intensity 17. Each of the assessment interfaces comprises an operable
graphical user interface (GUI) that may be operated by the clinician
and/or patient for assessing one or more sound attributes of the
patient's tinnitus. The workflow of some of the assessment interfaces may
be automated or semi-automated, or alternatively under complete control
of the operator. The assessment information obtained by the use of each
assessment interface may be stored electronically into a computer file or
files that contain the information representing the patient's subjective
tinnitus characterisation. The various assessment interfaces may interact
with each other, such that assessment information from one interface is
fed into one or more of the other interfaces. Optionally, the order of
operation of the various interfaces may also be controlled, such that the
tinnitus assessment for each patient follows a step-by-step protocol to
accurately characterise the patient's tinnitus. The system may be
operated by a clinician with the patient wearing the audio delivery
devices for the test sounds, or may alternatively be operated by the
patient as a self-assessment tool. As will be described with reference to
FIGS. 3-9, 11 and 12, the overall GUI for the tinnitus diagnosis system
may provide each assessment interface in a separate accessible tab, which
when selected displays the operable GUI for that assessment interface.

[0090] By way of example, in one embodiment the tinnitus diagnosis system
the sound format used may be 16-bit with a 44100 sampling rate. Monaural
sound may be used to generate the stereo spatial sound. The system may
support any sound format, including but not limited to the following
formats: .wav, .mp3, .wma, .pcm.

Calibration

[0091] Firstly, a patient calibration assessment 62 may be carried out in
the form of a behavioural calibration to determine the patient's absolute
hearing thresholds and uncomfortable loudness levels (audiogram). This
calibration assessment will be conducted using the audio delivery devices
that will be worn by the patient, for example headphones or hearing aids.
Such information may be determined from a patient's clinical audiogram in
some embodiments. In some embodiments, the calibration of absolute
hearing thresholds will be applied to compensate hearing at further
stages and therefore the further loudness will be controlled with sound
level (dB SL) upon the thresholds.

[0092] Referring to FIG. 3, in one embodiment of the method the
calibration assessment may be performed using the audiometer assessment
interface 150 of the tinnitus diagnosis system. In operation, the
audiometer assessment interface provides a measurement tool for hearing
thresholds for a range of frequencies. By way of example, the measurable
frequencies may be 125 Hz, 250 Hz, 500 Hz, 750 Hz, 1000 Hz, 1500 Hz, 2000
Hz, 3000 Hz, 4000 Hz, 5000 Hz, 6000 Hz, 7000 Hz, 8000 Hz, 9000 Hz, 10000
Hz, 11000 Hz, 12000 Hz, 13000 Hz, 14000 Hz, 15000 Hz and 16000 Hz,
although it will be appreciated that these frequencies may be altered as
desired.

[0093] For a new test, the filename for storing the audiogram information
may be entered into the filename box 153. Then, the main control panel
154 may be operated to sequentially generate test sounds at a desired
frequency and gain for either the left or right. The initiate button 155
initiates the playback of the selected test sound to the patient, and the
store button 156 saves the threshold result for that test sound frequency
upon the patient's feedback. After each frequency is tested and stored,
the audiogram results are plotted in the graphical display 157. The save
button 158 may be operated to store all threshold results into the
desired file entered into 153.

[0094] Alternatively, a previous audiogram performed by the patient on the
system may be loaded by entering the relevant filename into box 153 and
then operating the OK button 159 to load the previous results, which may
then be updated for all or a selection of frequencies.

Tinnitus Sound Attributes

[0095] The treatment method then involves determining the patient's
perceived tinnitus sound attributes 14, i.e. characterising the patient's
tinnitus. In this example, the bandwidth, temporal properties, loudness,
and pitch characteristics of the tinnitus as perceived by the patient are
tested and recorded by an audiologist or clinician. As is known to those
skilled in audiology, such tests typically present a series of sounds
with varying attributes and seeking the patient's feedback in relation to
the attributes that most closely match the sound attributes of the
tinnitus as they perceive it. By way of example, such audiologist
techniques that may be employed include pitch-matching and
loudness-matching. Tinnitus specific measures to see how the patient's
tinnitus compares with other environmental sounds may also be undertaken
to find a tinnitus sound match.

[0096] Referring to FIG. 4, in one embodiment of the method the pitch
matching assessment may be performed using the tone/bandnoise pitch match
function interface 160 of the tinnitus diagnosis system. The function
uses tonal or bandnoise stimuli with a 2AFC (2-alternative forced-choice)
method to determine tinnitus pitch-match. It allows for modification of
various parameters such as bandwidth and center frequency to promote a
close match to the tinnitus percept. Test ear selection panel 163 may be
operated to select either the left, right or both ears to test. The
stimuli selection panel 164 may be operated to select the type of
stimulus for the test sound playback, for example uniform white (white
noise) or sine (tonal). The intensity slider scale 165 may be adjusted to
set the desired intensity of the test sound. Operation of the start
button 166 initiates the test sounds for playback to the patient for
their feedback on pitch-matching to their tinnitus. Depending on their
feedback, the center frequency 167 and/or bandwidth 168 of the stimuli
may be adjusted to generate new test sounds to enable a closer
pitch-match. The process is repeated until the closest pitch-match is
obtained. The sound spectrum of the test sounds is displayed in the
spectrum graphical display 169. The save button 170 may be operated to
store the pitch-match results into a new or selected data file. A further
stop button 171 is also provided for halting the interface. The interface
compensates for any hearing loss as determined in the audiometer
assessment interface 150.

[0097] Referring to FIG. 5, in one embodiment of the method the loudness
matching assessment may be performed using the volume function interface
180 of the tinnitus diagnosis system. Upon initialisation, the interface
automatically plays a noise to the patient. The generated noise is
compensated for any hearing loss based on the audiometer assessment
interface 150 results. The user may then operate the main control panel
182 to adjust the volume slider scale to adjust the volume of the noise
to a comfortable and easily audible level. Additionally, the type of
sound may be selected between NBN (narrowband noise) at tinnitus pitch or
BBN (broadband noise). By way of example, NBN at tinnitus pitch supplies
more gain without peak-clipping, especially in the case of
steeply-sloping, high-frequency hearing loss. A peak clip indicator 183
is provided if the adjusted volume via the slider scale is likely to
introduce peak-clipping. A halt button 184 is provided to halt the
interface. The OK button 185 may be operated to store the user-adjusted
volume setting in a data file, which may then be used by subsequent
interfaces.

[0098] Referring to FIG. 6, in one embodiment of the method a tinnitus
sound matching assessment may be performed using a first tinnitus
sound-match function interface 190 of the tinnitus diagnosis system. The
purpose of this interface is to allow a patient to characterise their
subjective tinnitus percept via a sound library to help identify a
tinnitus sound-match from environmental sounds. The audiologist or
clinician may ask the patient to describe their tinnitus and then proceed
to play any suitably matching sounds to the patient for their feedback on
matching. It will be appreciated that the interface itself may
alternatively be configured to guide the patient through this process
automatically as a self-assessment tool if desired. A main sound library
panel is provided at 191 comprising sound category tabs 192, and for each
category one or more sound buttons 193 that are operable to playback a
sound of the type indicated on the button for the patient's feedback for
matching to their tinnitus. A volume/intensity presentation level slider
scale 194 is provided for adjusting the presentation volume of the test
sounds. The default volume level, is automatically set according to the
audiometric threshold values obtained by the audiometer interface 150.
The volume level may be adjusted to be softer or louder using the scale
194 depending on the patient's subjective tinnitus impressions. An
equaliser button 195 may be operated to adjust the sound frequency
components of the test sounds to improve sound quality if needed. The
sound file path in the sound library of the selected sound button may be
displayed to the user at 196. The sound library of different types of
sound files may be located locally in data storage on the host computer
system or an accessible external storage database. The closest
environmental sound match may then be recorded for the patient or stored
in a data file associated with the patient.

[0099] Referring to FIGS. 7-9, in one embodiment of the method a tinnitus
sound matching assessment may be performed using a second tinnitus
sound-match function interface 200 of the tinnitus diagnosis system. This
second interface 200 may be used as an alternative to the first interface
190 if the patient requires a larger sound library of environmental
sounds from which to assess a tinnitus sound match. In this embodiment,
the interface 200 has three main sub-interfaces, namely a find sound
interface 203, a format sound interface 204, and a sound player interface
205.

[0100] Referring to FIG. 7, the find sound sub-interface 203 offers a
search interface for searching the internet for environmental sounds for
playback. A website search interface may be loaded by entering a website
address into the URL bar 206. The website may be loaded into search panel
207 upon operation of the load button 208. The website address may for
example be a sound search interface for searching the internet, an
intranet or other database for sound files that match one or more
descriptive keywords and/or sound file parameters or a sound generation
website. The sound files located may then be played to the patient to
find the closest match to their tinnitus. The closest tinnitus-sound
match files may also then be downloaded and stored from the sound file
links.

[0101] Referring to FIG. 8, the format sound sub-interface 204 is
configured to convert any downloaded sound file from the find sound
sub-interface 203 as selected in the file path interface 212 into a
suitable format for use in the tinnitus diagnosis system. For example,
the format sound sub-interface may be configured to convert a sound file
into monoaural, 16-bit with a 44100 sampling rate, or any other desired
sound format and store the formatted sound file. Success 213 and error
214 indicators are provided to indicate whether the selected file has
been successfully formatted or not. A ramp button 215 is also operable to
apply a ramp function to the sound files to remove any audible pops,
clicks or distortion, if necessary.

[0102] Referring to FIG. 9, the sound player sub-interface 205 is
configured as an audio tool for playing back a preview of the sound found
via the find sound sub-interface 203, and which the patient perceives as
characterising or describing their tinnitus percept. The sound file to be
previewed may be selected using the file selection panel 216 and the
sound may be played to the patient or user by operation of the sound
start button 217. A volume adjustment is available via operation of
slider scale 218 to make the presentation softer or louder. The interface
is configured to initially default to a presentation level that
corresponds to the threshold values assessed in the audiometer interface
205. An operable equaliser button 219 is also provided for adjusting the
sound frequency components to improve sound quality, if needed. A stop
button 220 is provided to halt playback.

Generation of Tinnitus Synthetic Sound

[0103] Reverting to FIG. 2, after one or more of the assessments 62,14
have been conducted, whether via the tinnitus diagnosis system interfaces
or otherwise, the clinician generates a tinnitus synthetic sound 15 that
most closely matches at least one, but preferably all, sound attributes
of the tinnitus as perceived by the patient based on the information
obtained during the assessments. If the tinnitus diagnosis system is
used, all the assessment information from the interfaces may be stored in
one or more accessible data files associated with the patient and which
profile the characterisation of their tinnitus. For example, the
synthetic sound 15 generated may be a tone, noise, or environmental sound
that is further signal processed to match the patient's characterisation
of their tinnitus in terms of bandwidth, temporal properties, loudness
(intensity), and pitch, or any other assessed sound attributes. This
synthetic sound 15 may be utilised as the test sound in the next tinnitus
spatial information assessment step 16.

Tinnitus Location

[0104] The next step 16 involves the clinician assessing the spatial
information corresponding to the tinnitus as perceived by the patient. In
this embodiment, the clinician determines the 3D direction vector in 3D
auditory space from which the tinnitus sound appears to originate as
perceived by the patient. In this embodiment, the 3D direction vector is
represented angularly by azimuth angle θA and elevation angle
θE relative to a reference point or frame. It will be
appreciated that the spatial information relating to the perceived
tinnitus sound source direction or location may be represented in any
other suitable form of coordinate system if desired. In addition, it will
be appreciated that the spatial information may comprise a 3D direction
vector and magnitude to the perceived sound source location so that
distance as well as direction to the location can be used when generating
the spatial masking sound.

[0105] Referring to FIG. 10A, an example of the 3D direction vector 106 to
perceived tinnitus source location 100 is shown. In this example, the
reference point 102 represents the centre of a patient's head and the
circular reference plane 104 is located parallel to the transverse plane
of the human anatomy i.e. it extends horizontally from the back of the
head to the front of the head when upright. In one form, the reference
point may be the center of the midline axis between the patient's left
and right ears. The 3D direction vector 106 to the perceived tinnitus
source location is represented by azimuth angle θA
representing the azimuth angle of the 3D direction vector 106 relative to
reference vector 108 in the circular reference plane 104 and elevation
angle θE representing the angular elevation of the 3D
direction vector 106 relative to the circular reference plane 104, which
may be above or below the plane between 90 and -90° The azimuth
angle θA may be anywhere between 0-359°.

[0106] As will be explained in more detail later, the sound generation
system employs virtual acoustic technology to generate the test sound to
appear to originate from a direction in 3D auditory space that
corresponds to the azimuth and elevation desired.

[0107] In one embodiment, the sound generation system is configured to
sequentially generate a series of spatial sounds that are presented to
originate through an azimuth angle of between 0-359° (elevation
angle =0°) in the circular reference plane 104 in order to match
to the tinnitus azimuth. As the series of test sounds (for example the
tinnitus synthetic sound 30) are sequentially played through the azimuth
range, feedback is received from the patient as to the test sound that
most closely corresponds to the spatial location or direction from which
their tinnitus is perceived as originating from. Once the tinnitus
azimuth is located, spatial sounds at that specific azimuth are presented
to originate through an elevation range of between -90° to
90°, and feedback is received from the patient as to the elevation
angle that most closely corresponds to the tinnitus source location as
they perceive it. In one form, the test sounds may be swept continuously
through the azimuth and elevation ranges. In another form, the test
sounds may be sequentially presented at discrete equi-spaced azimuth and
elevation angles in the ranges or alternatively at non-uniformly spaced
azimuth and elevation angles in the ranges as desired.

[0108] It will be appreciated that other testing processes may
alternatively be used to assess the tinnitus azimuth and elevation
angles. For example, the elevation angle may be assessed prior to the
azimuth angle if desired. A further alternative may involve presenting
the test sounds through azimuth and elevation angle ranges concurrently,
i.e. present the elevation range at each azimuth angle or vice versa. In
addition to detecting the direction of the perceived tinnitus sound
source, the intensity of the test sounds may be varied so as to enable
assessment of the perceived distance of the tinnitus sound source
location relative to the reference point.

[0109] In another embodiment, the sound generation system may be operable
and controllable by the clinician or patient to manually vary the 3D
spatial location (azimuth and elevation) of the test sound as desired to
find a location match. By way of example only, the sound generation
system may form part of the tinnitus diagnosis system. Referring to FIG.
11, a 3D spatial location interface function 250 of the tinnitus
diagnosis system may be operable to present a test sound to the user such
that it appears to originate from a desired 3D spatial location. The test
sound file for playback at the desired location may be selected using
file selection panel 251. The sound file may be the synthetic sound file
generated at step 15 or any other desired test sound. The user may select
the pinna size of the listener, for example normal pinna or large pinna
using selection options 251,252 and this will configure the system to
more accurately locate the test sound in virtual 3D space for the user
using virtual acoustic technology. A diffuse field button 253 may be
operated to clean the sound signal, depending on the type of test sound
that has been selected. Operation of the start sound button 254 initiates
playback of the test sound to the patient.

[0110] The interface 250 is configured to provide a display grid 258 that
represents the spatial location 255 of the test sound presented in a
reference frame relative to the center of the patient's head as shown at
C. The Cartesian coordinates of the spatial location of the test sound
are displayed at 256, and the elevation and azimuth displayed in
interface 257. The clinician or patient may drag and drop the cursor 255
around the display grid of the GUI to alter the spatial location of the
test sound presented so as to find the closest match to the tinnitus
location as perceived by the patient. Each time the cursor is placed in a
new position the spatial playback properties of the test sound are
altered to correspond to the new location. In this embodiment, the
display grid 258 represents the azimuth of the test sound location and
the user may configure this first by locating the cursor 255 at a
position on the grid that represents whether they perceive their tinnitus
to be originating. By way of example, the top of the grid may represent
the front of the head, the bottom of the grid the back of the head, and
the left and right sides of the grid may represent the left and right
sides of the head respectively. Once the azimuth of the perceived
tinnitus location is determined, the user may then find the elevation of
the perceived tinnitus location relative to the midline axis between
their ears, i.e. whether the patient perceives their tinnitus to be
originating in a plane located at the midline (0° elevation) or
plane above or below the midline. To adjust the elevation, the user may
use the slide scale 259 to adjust the elevation of the test sound
presented. Once the user has located the test sound in a position that
most closely matches their perceived tinnitus location, they may save
this spatial information into a data file by operating the save button
260. A halt button 261 is also provided for halting the interface if
desired.

[0111] The perceived tinnitus source location does not necessarily have to
be represented in 3D auditory space by azimuth and elevation angles
relative to a reference point. In another forms, the 3D auditory space
may be represented by three-axis Cartesian coordinates (X, Y, Z) as shown
in FIGS. 10B and 10C. For example, the origin of the 3-axis orthogonal
reference frame may again be the center of the midline axis between the
patient's ears and this midline axis may be the X-axis. The Y-axis is
orthogonal to the X-axis and extends horizontally between the front and
back of head, as shown in the display grid 258 of the 3D spatial location
interface function 250 for example. The Z-axis is orthogonal to the X-Y
plane and extends vertically between the top and bottom of the head.
Based on this reference frame, the patient's perceived tinnitus location,
such as a 3D direction vector, may be defined by 3-axis X,Y,Z
coordinates. The X, Y, Z axes may extend external to the patient's head.

Tinnitus Intensity at 3D Location

[0112] Reverting to FIG. 2, the next stage 17 is evaluating one or more
intensity levels for the test sound as perceived by the patient at the
spatial location determined in the location assessment 16. The following
levels may be determined: the threshold level (THL) at which the sound at
the perceived tinnitus location can be detected, the minimum amount of
intensity required for this sound to mask or cover the patient's tinnitus
percept (MML--minimum masking level), and the amount of intensity
perceived to be as loud as the patient's subjective tinnitus percept
(LVL). Sensation level methods may be employed to determine the MML.
Residual inhibition tests for determining the occurrence, following the
presentation of a masking sound, of temporary (partial or complete)
suppression of an individual's tinnitus may be carried out. Loudness
growth and discomfort tests may be carried Out in the form of a
standardised measurement of loudness perception.

[0113] Referring to FIG. 12, in one embodiment, the tinnitus diagnosis
system provides a tinnitus intensity assessment interface 270 that may be
operated by a user to determine one or more of the intensity levels MML,
THL, and LVL. The interface 270 is operable to present a test sound, such
as the generated synthetic sound 15 or otherwise, at the spatial location
corresponding to the patient's perceived tinnitus at various intensities
for assessing the thresholds. The test sound file may be selected at file
selection interface 271. The type of test or assessment being conducted,
for example MML, THL or LVL, may be selected in panel 272. Playback of
the sound file is initiated via the interface and may be repeated for a
number of desired iterations as selected at 273 with the playback time
remaining being displayed at 274. During playback, the user may adjust
the volume slider scale 275 to adjust the intensity level to suit the
level being assessed, i.e. MML, THL, LVL. Once the volume has been
adjusted for each test level, the results or intensity level information
are saved to a data file as triggered by operation of the save button
276. A halt button 277 is also provided to halt the interface at any
point if desired.

Set Personalised Masking Sound Parameters

[0114] Once the tinnitus diagnosis stage 12 is complete, the sound
attributes information, spatial information, and intensity level
information relating to the tinnitus as perceived by the patient is used
as input for the next step of setting the personalised masking sound
parameters 18. As previously indicated, the assessment information may be
stored in an accessible electronic data file or files, or recorded in any
other suitable form. Firstly, a new masking sound may be created or a
previous stored masking sound selected at step 36 for loading into the
remainder of the process. If a previous masking sound is selected, then
the sound parameters of that sound will be personalized for the patient
in view of the information from the tinnitus diagnosis stage. If a new
masking sound is to be created, then a stimulus will need to be selected
from a masking sound library and the sound parameters of that stimulus
personalised in view of the information from the tinnitus diagnosis
stage. This library may include for example, but is not limited to, white
noises, low frequency noises, fractal sounds, pseudo-random varying
frequency tones (e.g. piano tones and the note), natural sounds (e.g.
rain) or any other suitable therapy sounds. Alternatively, the tinnitus
synthetic sound 15 generated in the tinnitus diagnosis stage 12 can be
loaded for the next masking parameter setting stage 18.

[0115] The next step 38 in personalisation of the masking sound is
locating the spatial position of the 3D spatial masking sound by
selecting target azimuth and elevation angles. These angles are
configured to correspond or match the tinnitus azimuth and elevation
angles of the spatial information as assessed in the tinnitus diagnosis.
step.

[0116] The next steps 42 comprise modifying the selected stimulus of the
new masking sound or the pre-stored masking sound by tuning various sound
attribute parameters, such as the bandwidth, temporal property, loudness,
and pitch. In some embodiments, one or more of the sound attributes may
be tuned so as to substantially correspond to one more of the
corresponding parameters of the perceived tinnitus as determined in the
diagnosis step 12. As to loudness tuning, this can also be used to match
the Minimum Masking Level (MML), Minimum Effective Masking Level (MEML)
and Desired Masking Level (DML) of the spatial masking sound at the
virtual 3D sound source location for the individual patient, and which
may be assessed in the calibration phase 62. MML represents the minimum
level of sound required to cover the tinnitus making it inaudible. MEML
represents the minimum level of sound that the listener finds effective
in reducing tinnitus audibility. DML represents the level of sound the
listener prefers to use to mask their tinnitus.

Set Additional Sound Processing Parameters

[0117] After personalisation of the masking sound has been configured,
additional optional sound processing parameters 20 may be configured.
These steps may be optional depending on the spatial masking sound
desired and the tinnitus treatment plan being employed by the patient. By
way of example only, the play time 60 for the masking sound file may be
set and the diffuse-field 46 for the spatial masking sound may be
configured to match a desired profile. For example, the diffuse-field may
be configured such that the flow of sound energy is substantially equal
in all directions from the virtual 3D tinnitus source location or
alternatively the diffuse-field may be configured to focus the sound
energy in one or more particular directions or regions.

[0118] Optionally, the intensity of the masking sound may be modulated
according to a ramping profile. For example, a ramp parameter or profile
48 may be set and applied to the masking sound in order to vary the
intensity or loudness of the sound over time in accordance with a
predetermined profile. FIG. 13A shows a possible periodic ramping
architecture with configurable parameters that may be applied to the
masking sound to vary its intensity/volume during playback. As shown, the
ramping profile may comprise a series of periodically repeating uniform
ramps (only two shown at R1, R2). The ramps initiate with a gradual gain
280 relative to the un-ramped original signal level 281 having a rise
time period indicated at 282 such that the rate of increase may be
adjusted. At the end of the initial gain, the ramp may then be maintained
at the upper level 283 for a steady state period indicated at 284 until
undertaking a gradual drop in gain back to the un-ramped original signal
level 281 as shown at 285 over a fall time period 286 such that the rate
of decrease may be adjusted. The overall duration of the ramp is
adjustable and shown at 287. The interval time period 288 between the
ramps is also adjustable, and there may be no interval in some ramping
profiles such that the ramping modulation of the volume of the masking
sound is continuous.

[0119] It will be appreciated that all the parameters of the ramping
profile outlined above may be adjusted to generate a desired ramping
profile to apply to the masking sound to modulate its intensity. By way
of example only, FIG. 13B one possible example of a ramping profile is
shown in the form of a saw-tooth profile that may be applied to the
masking sound to alter its intensity level over time. As shown, the
ramping profile has a saw tooth pattern comprising a series of
alternating gradual increments and rapid decrements in intensity level.
In the saw-tooth profile, there is no interval between the successive
ramps. The intensity rise time 290 is long and gradual, and is followed
by an intensity drop time 291 that is shorter and abrupt. In this
example, there is no steady state period 284 between the intensity
increase and decrease periods. The alternating gradual increments and
rapid decrements in intensity enhance and maintain a person's attention
to sound over time, and this assists the patient to attend to the masking
sound in favour of their tinnitus. The ramping profile maintains
attention by modulating the sound as a sequence of stimulus ramps, where
intensity increases are small and incremental, but stimulus decreases are
large and abrupt. It will be appreciated that alternative intensity
profiles or patterns may be applied. For example, the pattern may
alternatively be in an arc-type as opposed to saw-tooth, or any other
periodic or repeating ramping profile.

Generation of Spatial Masking Sound

[0120] The next stage 22 after the configuration of the sound processing
parameters comprises generating the customised 3D spatial masking sound
54 using audio processing systems (including, for example, onboard audio
processing systems in hearing aids and/or headphones) and/or software in
accordance with the parameters set in the personalisation step 18 and
sound processing step 20. In one embodiment, the synthetic tinnitus sound
15 (which has one or more of its sound attributes matching the
corresponding perceived sound attributes of the patient's tinnitus) has
its spatial playback properties altered using virtual acoustic sound
localisation algorithms and techniques such that it appears to originate
from the patient's perceived tinnitus source location during playback
over left and right ear-level audio delivery devices. The playback time,
diffuse field and any ramping profile are also configured for the masking
sound in accordance with the configuration parameters. It will also be
appreciated that the 3D spatial making sound 54 generated may be any
stimulus sound that is signal processed and modified in accordance with
the parameters set in steps 18 and 20. A test playback 56 of the
generated masking sound 54 may be played for monitoring with headphones
via a programmable attenuator and headphones buffer. If the playback
results are favourable at decision point 58, the spatial masking sound is
compiled into a digital or electronic sound file 64 or other sound
recording for storage on a suitable medium that can be accessed and
played by a sound delivery system. In some embodiments, the 3D spatial
masking sound is represented in the form of stereo left and right ear
audio signals for playback over left and right ear-level audio delivery
devices. If the playback results are not favourable, the personalisation
and sound processing parameters may be reconfigured as desired, and the
masking sound regenerated.

[0121] The virtual acoustic technology and examples of hardware systems
for generation and/or playback of the spatial masking sound will now be
described in more detail.

3. Virtual Acoustic Processing Technology--Sound Localisation

[0122] The virtual acoustic technology employed in the tinnitus location
diagnosis step 16 and the spatial masking sound generating process step
54 employs the use of sound localisation techniques. Various techniques
for altering the perceived location of sound in 3D auditory space are
known including using any one or more of the following, in combination or
alone, Interaural Time Difference (ITD), Interaural Level Differences
(ILD), and Head-Related Transfer Functions (HRTFs). ITD and ILD tend to
be used to vary the perceived lateral location of the sound along the
midline axis between a person's ears, but HRTFs enable sound to be
localised outside of the head and at any desired elevation.

[0123] The use of HRTFs is known in audio and sound technology field for
creating virtual acoustic spaces. HRTFs describe how a given sound wave
(parameterised as frequency and source location) is filtered by the
diffraction and reflection properties of the head, pinna, and torso,
before the sound reaches the transduction machinery of the ear drum and
inner ear. In brief, the HRTF defines how the head and outer ears filter
incoming sounds. As is known to those skilled in sound technology, the
HRTFs can be measured by placing miniature probe microphones into the
patient's ears and recording a bank of impulse responses to broad-band
sounds presented to the subject from a range of directions in space.

[0124] The impulse responses are sampled in time and a bank of associated
HRTFs may be formulated by Fourier transform of the impulse responses.
There are two head-related transfer functions, HRTF_L, HRTF_R. (one for
the left ear and one for the right ear) for each sound direction tested.
The HRTFs describe the phase and magnitude response at each ear as a
function of frequency, relative to the sound that would received at the
centre of the head in the absence of the listener.

[0125] The bank of HRTFs for the various sound locations may then be used
to generate sounds in specific locations in virtual 3D acoustic space. A
spatial sound signal, for example a binaural or stereo audio signal,
appearing to originate from a virtual sound source location in 3D
auditory space can be created from a monophonic source signal by
filtering or convolving that monaural signal with the inverse of the left
and right ear HRTFs associated with the desired virtual location. Playing
back the binaural audio signals directly into the ears, for example via
headphones, creates the illusion of the sound originating from the
virtual sound source location.

[0126] HRTFs vary from individual to individual and therefore the use of a
customised bank of HRTFs measured from the individual patient is
beneficial. However, average or ideal HRTFs are known and can be utilised
instead of customised HRTFs.

[0127] Referring to FIG. 14, an example of the virtual acoustic technology
hardware setup is shown. The input sound signal, such a monaural signal
300 may have any desired ramp profile applied by a ramp module 301 via
modulation with a ramping signal 302, although this is optional. The
ramped signal is then filtered through left and right ear impulse
responses obtained from the inverse Fourier transforms of the left and
right ear HRTFs for the determined tinnitus sound source direction
(azimuth and elevation). In other words, the ramped digital input signal
is convolved with the inverse Fourier transform of the left and right ear
HRTFs at 304a and 304b. The left and right signals may then be filtered
through diffuse-field equalisers 306a, 306b and attenuators 308a and 308b
if desired. The diffuse field equalisers 306a,306b may be configured
based on the parameters set in 46. The diffuse-field may be configured
such that the flow of sound energy is substantially equal in all
directions from the virtual 3D tinnitus source location or alternatively
the diffuse-field may be configured to focus the sound energy in one or
more particular directions or regions. The attenuators 308a,308b may be
configured based on the audiometer assessment information obtained during
the calibration 62. The resulting left 310a and right 310b output signals
are then played to the patient via stereo audio devices, such as binaural
hearing aids, headphones or earphones or the like.

4. An Example Embodiment of the Hardware Implementation of the Tinnitus
Treatment System

[0128] Various sound delivery systems and devices may be employed to
deliver or present the 3D spatial masking sound to the patient. Some
possible examples of systems and devices for carrying out this function
will now be described by way of example only with reference to FIGS.
15a-20.

4.1 Tinnitus Treatment System Using Hearing Aid Devices

[0129] Onboard Sound Storage and/or Generation

[0130] In one embodiment, the sound delivery system for presenting the
spatial masking sound to the patient may comprise left and right hearing
aids driven by a common external audio controller and which have onboard
circuitry for storing and/or generating the spatial masking sound.

[0131] Referring to FIG. 15a, a first form of hearing aid circuit 400 is
shown. In this tinnitus treatment system similar left and right hearing
aid circuits are employed although only one is shown for clarity. Each
hearing aid circuit comprises a stimuli storage module 402 that is
arranged to receive and store the spatial masking sound file, for example
uploaded to the hearing aid from an external device such as a personal
computer 404 or the like. The hearing aid circuit includes a control unit
406 that communicates with an external remote audio control device 408.
In this form of the system, the control unit 406 communicates with the
remote control device 408 wirelessly although hardwired connectivity
could alternatively be used.

[0132] In operation, there is a user interface in the form of a single
remote controller 408 which simultaneously communicates with both the
left and right hearing aid circuits. The patient may operate the remote
controller to initiate playback of the spatial masking sound by sending a
trigger signal 410 to each respective control unit. On receiving this
trigger signal 410, the control unit 406 is arranged to send a trigger
signal 412 to the stimuli storage module 402 that contains the masking
sound file and to initiate playback. In this form of the system, the
stimuli storage module 402 for the left hearing aid circuit retains the
left channel audio signal of the stereo spatial masking sound and the
stimuli storage module of the right hearing aid circuit retains the right
channel audio signal.

[0133] In this embodiment, a ramp unit or module 416 in each hearing aid
circuit is configurable to apply a ramping profile to the spatial masking
sound signal via a ramping signal 417 to modulate the intensity or
loudness of the playback in accordance with a desired ramping profile, as
previously explained. It will be appreciated that the ramp unit 416 may
be deactivated if no ramping modulation is to be applied.

[0134] In their respective circuits, the left and right audio signals 414
after being multiplied by any desired ramping signal 417 are received by
the hearing aid processor 420 of the circuit where they are buffered and
amplified, and transmitted to the hearing aid speaker 422 for playback of
the audio sound into the patient's left and right ears respectively.

[0135] The left and right hearing aid circuits are synchronised such that
the playback of their respective left and right audio signals,
representing the spatial masking sound, creates playback of the masking
sound so as to appear to originate from a virtual sound source location
that substantially corresponds to the tinnitus source sound location as
perceived by the patient.

[0136] Referring to FIG. 15b, a second form of hearing aid circuit that
may be employed in a tinnitus treatment system comprising left and right
hearing aids synchronously controlled by a remote controller is shown. In
contrast to the first form hearing circuit that stores the respective
left and right audio signals of the spatial masking sound onboard for
playback, the second form hearing aid circuit 500 comprises an onboard
sound processor, such as a 3D synthesiser 502, that is arranged to
generate the left and right audio signals in real-time for delivering to
the patient.

[0137] As with the first preferred form of hearing aid circuit, a single
remote controller 504 is arranged to communicate with each of the left
and right hearing aid circuit and control the synchronised generation of
the left and right audio signals representing the spatial masking sound.
For example, the remote controller is arranged to send trigger signals
510, via wireless or wired connection, to the 3D synthesiser, circuits
502 of each respective hearing aid circuit. In response to this trigger,
a noise generator 508 generates a monaural masking sound 506 that is then
subjected to sound processing to create the spatial and other sound
attribute properties required of the masking sound when ultimately
delivered by the left and right hearing aid circuit.

[0138] By way of example, the monaural sound signal generated by the noise
generator 506 may be selected from a range of stimuli, including white
noise, music, tones, background noise, sound effects or the like. On the
initiation of the monaural sound signal generation, a simultaneous
trigger signal 512 is sent to initiate ramp 519 and HRTF 516 signals that
are arranged to modify the monaural signal 506. In particular, a ramp
module 518 generates the ramp signal 519 that modulates the monaural
signal 506 in accordance with a desired ramping profile. The HRTF module
520 for each circuit is arranged to generate an HRTF impulse response
signal 516 that is convolved with the ramped monaural signal so as to
generate the spatial property for the respective left and right audio
signals such that when delivered to the patient they combine to present a
masking sound that appears to originate from a virtual sound source
location substantially corresponding to the 3D spatial location as
perceived by the patient. As before, the ramp module 518 may be
deactivated if no ramping of the masking sound is required.

[0139] The modified left and right signals 522 (from each of the left and
right hearing aid circuits) then together represent the spatial masking
sound. The hearing aid processor 524 of each circuit is again used to
amplify and buffer the respective modified left and right signals for
sending to the speaker 526 of each hearing aid so as to deliver the sound
to the patient. In an alternative form, the 3D synthesizer may be
implemented or incorporated in the hearing aid processor 524

[0140]FIG. 16 shows the hardware devices of the tinnitus treatment system
that may be employed to implement either forms of the hearing aid
circuits described with reference to FIGS. 15A and 15B. By way of
example, left 610a and right 610b hearing aids for a patient to wear are
shown. The playback of the spatial masking signal via the hearing aids is
controlled synchronously by an external remote controller 600 that sends
the hearing aids respective control signals 612a, 612b wirelessly, for
example using Near Field Magnetic Induction (NFMI), Bluetooth, FM,
infrared, or any other wireless transmission. The remote controller may
alternatively be hardwired via cable(s) to the hearing aids if desired.

External Sound Storage and/or Generation

[0141] In another embodiment, the sound delivery system for presenting the
spatial masking sound to the patient may comprise conventional left and
right hearing aids driven by a common external audio control device that
is arranged to store, generate, and/or send the left and right audio
signals representing the spatial masking sound to the hearing aids for
playback.

[0142] Referring to FIG. 17, this embodiment of the tinnitus treatment
system comprises an external audio control device 700 that is arranged to
send left and right audio signals to respective left and right hearing
aid circuits 702 (only one shown for clarity) for playback. In one form,
the audio control device 702 may comprise a storage memory module 704 for
storing the spatial masking sound and/or stimuli sounds for generating
the spatial masking sound. Such stimuli sounds may include sounds that
are configured to match one or more of the patient's perceived tinnitus
sound attributes. A sound processor module 706, such as a 3D synthesiser,
is provided for generating the left and right audio signals representing
the spatial masking sound using virtual acoustic space processing in
real-time of the stimuli sounds from memory 704. The 3D synthesiser may
operate in a similar manner to that described with reference to the 3D
synthesiser of FIG. 15b by altering the spatial properties of the stimuli
sounds to create a virtual sound source location that corresponds to that
of the perceived tinnitus source location.

[0143] The sound processor module 706 may be provided in the form of a
programmable hardware device, such as a Digital Signal Processor (DSP) or
any other programmable microprocessor. In addition to implementing a 3D
synthesizer function to generate the real-time spatial masking sound, the
sound processor module may also be arranged as an audio player. The audio
player may be provided with a user interface that is operable to control
delivery (e.g. playback) of the masking sound, such as start, stop and
pause functions, and other typical audio parameters such as volume.

[0144] The audio player of the sound processor module 706 can be
configured to control generation of the masking sound by the 3D
synthesizer and presentation/delivery of the sound to the audio delivery
devices, and/or can be configured to load and control playback of masking
sound audio files that have been preloaded or stored in storage memory
module 704 or which are received via the input/output port 708 explained
below. In other embodiments, the sound processor module 706 need not
necessarily include a 3D synthesizer for generating masking sounds and
could be arranged only as an audio player that controls playback of
stored masking sound files in memory 704 or received from the
input/output port 708.

[0145] An input/output port 708 is provided for receiving sound files and
for controlling the sound processing parameters and configurations to
generate the desired spatial masking sound for playback. A user interface
may also be provided for controlling the generation and playback of the
spatial masking sound. The user interface may be integrated with the
audio control device 700 or an external device that communicates with the
control device via the input/output port 708. The user interface may be
provided in the form of any suitable electronic user interface,
including, but not limited to, buttons, dials, switches, touch-screen or
any combination thereof. An input/output transmission module 710 is
provided to enable wireless or wired connectivity and communication with
each of the left and right hearing aid devices.

[0146] When playback of the spatial masking sound is initiated by a user
operating the audio control device 700, the left and right audio signals
711 generated by the 3D synthesiser and/or provided from the storage
module 704 are simultaneously and synchronously sent to the respective
audio input modules 712 of the respective hearing aid circuits (if
hardwired to the audio control device) or to the respective wireless
receiver modules 714 if wireless communication is employed. The audio
signals 711 are then received and processed by their respective hearing
aid processors 716, for example they may be buffered and amplified, and
then sent to the respective left and right hearing aid speakers 718 for
playback to the user.

[0147] FIGS. 18 and 19 show a range of various hardware devices that may
be employed to implement the tinnitus treatment system of FIG. 17. As
mentioned the system comprises left and right audio delivery devices in
the form of left and right hearing aids that are controlled by an audio
control device or devices 802. The audio control device may be provided
in various forms with varying capabilities. For example, in some forms
the audio control device may simply store, transmit and control playback
of the spatial masking sound, but in other forms the audio control device
may have sound processing capabilities such that it is also operable to
generate and modify the spatial masking sound. It will also be
appreciated that these functions may be spread over multiple
interconnected or communicating devices.

[0148] In one form 804, the masking sound is stored on a remote device 806
that transmits and controls playback over the hearing aid devices 800.

[0149] In another form 808, the audio control device may comprise any
suitable generic sound or audio player or device having such
functionality, such as a Personal Computer 810, portable audio player
812, PDA 814 or the like, that is arranged to generate, store and/or
control playback of the spatial masking sound. The audio player may send
the left and right audio signals representing the spatial masking sound
directly to the hearing aids 816 or indirectly via other intermediate
transmission or control devices. For example, such intermediate control
devices may comprise a remote control device 818 or wireless transmission
device 820. It will be appreciated that connection and communication
between the audio player and any intermediate control devices may be
wirelessly, for example using NFMI, Bluetooth, FM, infrared or any other
wireless communication protocol, or via wired cables, or a combination of
the two.

[0150] In another form 830, the audio control device 820 may be in the
form a wireless transmission device that is arranged to store, transmit
and control playback of the spatial masking sound via wireless
communication with the hearing aids 800. In this form, the spatial
masking signal may be uploaded onto the audio control device 820 in the
form of a digital sound file for playback via an onboard audio player
that can process the sound file and generate the audio signals for
transmission to the hearing aid devices 800.

4.2 Tinnitus Treatment System Using Headphones

[0151] In another embodiment shown in FIG. 20, the sound delivery system
may comprise audio delivery devices in the form of standard left and
right headphones 900, ear buds or earphones that are worn by the user and
from which the left and right audio signals representing the spatial
masking sound is played.

[0152] It will be appreciated that the audio signals may be transmitted to
the headphones 900 from any suitable audio control device that is capable
of storing, generating and/or controlling playback of the spatial masking
sound. For example, the audio control device 902 may be in the form of a
Personal Computer, portable audio player, PDA, cell phone or any other
suitable device. Wireless headphones may alternatively be used and in
which case a wireless transmission device 906 integrated or external to
the audio control device 904 may be employed to transmit the audio
signals to the headphones for playback.

[0153] In other embodiments, the sound delivery system may comprise left
and right audio delivery devices that are integrated with one or more
onboard audio control devices rather than having an external audio
control device. The onboard audio control device may store the masking
sound file for playback or generate the masking sound in real-time, and
is operable via a user interface to control synchronised playback of the
left and right audio signals over their respective left and right audio
delivery devices to generate the audible spatial masking sound for the
patient. In one form, the sound delivery system may be a standalone
treatment system. In another form the sound delivery system may be
integrated into another device or expand the functionality of another
device. For example, the sound delivery system may be integrated into
twin left and right hearing aid system with onboard audio control for the
spatial masking sound playback. The left and right hearing aids may
communicate wirelessly to coordinate synchronised playback of the left
and right audio signals representing the spatial masking sound.

[0154] In summary various sound delivery system embodiments are possible
and the audio control device may be completely or partially integrated
with the audio delivery devices or entirely separate and external.

[0155] The foregoing description of the invention includes preferred forms
thereof Modifications may be made thereto without departing from the
scope of the invention as defined by the accompanying claims.

Patent applications by Kei Kobayashi, Waitakere NZ

Patent applications by AUCKLAND UNISERVICES LIMITED

Patent applications in class Ear or testing by auditory stimulus

Patent applications in all subclasses Ear or testing by auditory stimulus